Discrete event simulation frameworks, like SimPy, are a great mathematical way to simulate the environment if wanting to discover better methods of any methodoical staging flow. Elevator scheduling is one example that can be simulated.
Show HN: Elevators
341–350 of 427 posts
Re: Show HN: Elevators
#342> The simplest elevator algorithm is called SCAN and was patented in 1961. The elevator starts at the lobby and goes all the way to the top floor before reversing and coming back down. It picks up and drops off anybody on the way.
Patents, everybody...
Re: Show HN: Elevators
#343Back in highschool, simulating different elevator algorithms was one of the projects I implemented during my CS class. It wasn't for the class — AP CS did not require anything like actual programming — but it was a fun project. A cool connection is that a spinning-disk hard drive (HDD) is actually kind of like one really long elevator, just wrapped around a spindle instead of perfectly vertical. The SCAN algorithm is…
We did this in college as well using microcontrollers and leds or something - i forget the exact details. It was super fun
Did exactly the same with Assembly language on a PIC16C84 microcontroller with LEDs dyeing my university years a looong time ago.
Re: Show HN: Elevators
#344The biggest problem I always have with elevators is not the algorithm, it's the people seemingly being unable to grasp the concept of pressing either the up or the down request button, depending on where they want to go. Almost always I find someone will press both, because "then the elevator comes faster". Completely ignoring the fact that they end up going the wrong way first half the time, and adding an unnecessar…
Yes, same here, in croatia people believe that you need to press the opposite direction to "summon" the elevator, if the elevator is on lower floor they will press the "up" arrow to bring it up to their floor. And then of course when the doors open they will ask "going up or down?", which is ridiculous. When I point out that the ground floor only has the "up" button they just ignore it (hard to unlearn ingrained beli…
> in croatia people believe that you need to press the opposite direction to "summon" the elevator, if the elevator is on lower floor they will press the "up" arrow to bring it up to their floor
this is hilarious
Re: Show HN: Elevators
#345Earlier quoted context omitted.
The elevator algorithm → disk scheduling connection is such a perfect example of how CS concepts keep showing up in unexpected places. Same idea, completely different domain. It makes me wonder how many other "unrelated" problems we're solving today already have decades-old algorithms waiting to be rediscovered for them. Robot motion planning is basically just elevator scheduling with more degrees of freedom.
FYI: all your comments are [flagged][dead] I don't know why, because they all look fine to me...
LLM text tells, particularly in their other comments. Definitely AI generated.
Re: Show HN: Elevators
#346Earlier quoted context omitted.
And then when the elevator door opens, they ask the people inside: "Are you going up or down?" There's an arrow showing that, for Christ's sake.
The direction is also indicated by the chime sound, which only blind people and YouTube viewers seem to know. As for button pressing: https://en.wikipedia.org/wiki/Cargo_cult#As_a_metaphor
TIL! I need to keep an ear open for this.
Re: Show HN: Elevators
#347All I want to know is why the heck I can't un-press a button I pressed by accident. This should be very simple. Press once to turn the button on, press again to turn it off. Or I guess you could do long-press to turn off or something if you're worried about confusing people, but I really don't think that should be necessary. We know how toggles work. The button lights up when it's on.
In some elevators there is a stop lever for emergencies, but I found out it cleared all the selected floors as well. So in my building if I've made a mistake or a kid selected all the floors, I can just flip the stop toggle and reset everything.
OMG, this brings out memories about that oh so tempting red stop lever I was absolutely NOT allowed to touch as a kid. I haven't remebered that for decades..
Re: Show HN: Elevators
#348Re: Show HN: Elevators
#349All I want to know is why the heck I can't un-press a button I pressed by accident. This should be very simple. Press once to turn the button on, press again to turn it off. Or I guess you could do long-press to turn off or something if you're worried about confusing people, but I really don't think that should be necessary. We know how toggles work. The button lights up when it's on.
In some elevators there is a stop lever for emergencies, but I found out it cleared all the selected floors as well. So in my building if I've made a mistake or a kid selected all the floors, I can just flip the stop toggle and reset everything.
In my building there are fire extinguishers for emergencies, but I found out they produce a really amazing snow-blanket effect even when it's not Christmastime.
Re: Show HN: Elevators
#350Earlier quoted context omitted.
This is case where you need to make sure your test data reflects real-world usage or you end up optimizing for the wrong thing. Ideally a new elevator installation would have a trial period where they record usage and then run it through a simulator like this to determine the optimal strategy for that particular building. And you'd want to re-run it every once in a while as the building tenants/usage changes. I wonde…
> Ideally a new elevator installation would have a trial period where they record usage There's a tricky problem here: as a user, the first thing you do upon discovering a new elevator, especially if you expect to be using it regularly, is to observe how it behaves and adjust your own expectations/behavior to it.
Things are constantly changing. For example, a new building might have two or three tenants, so entire floors can be skipped. But then five years later, the whole building is full. I would bet that every new algorithm after LOOK is just differentiation in a competitive market.